Final answer:
A reed stylus was the tool used to create cuneiform by pressing into wet clay. This ancient writing system developed by the Sumerians was vital for documenting various aspects of Mesopotamian life and evolved into a sophisticated script over time.
Step-by-step explanation:
The tool that was pressed into clay to create cuneiform was a specially shaped reed stylus. This writing technique was developed by the Sumerians in ancient Mesopotamia, around 3000 BCE, primarily as a method to record information such as transactions and laws. Cuneiform, which comes from the Latin cuneus meaning 'wedge' and form shaped, was comprised of wedge-shaped marks made in wet clay that could be baked to preserve the writing.
These clay tablets often contained details of everyday life, economic exchanges, and were an important part of the historical record, providing insights into the complex and rich Mesopotamian culture. The evolution of cuneiform from pictograms to phonetic script allowed for a more efficient and sophisticated system of writing that was used for various types of records, including literature and legal codes.